中文摘要：

目的探讨低氧预适应（hypoxic preconditioning，HPC）和大脑中动脉阻塞（middle cerebral artery occlusion，MCAO）对小鼠脑内microRNAs表达的影响。方法借助已建小鼠整体HPC和脑MCAO模型，应用miRNA芯片方法观察HPC小鼠脑皮层和MCAO小鼠脑缺血半影区内miRNAs的差异表达。结果在656个miRNAs探针中，与Control组相比，HPC组小鼠脑皮层组织内鉴定出17个miRNAs的表达发生了明显改变。与Sham组相比，MCAO小鼠脑缺血半影区内鉴定出65个miRNAs的表达发生了显著变化（P〈0．05，n=12）。与MCAO小鼠脑缺血半影区相比，HPC＋MCAO组小鼠脑缺血半影区内有33个miRNAs的表达发生明显变化（P〈0．05，n=12）。基于DiffScore=±13（P=0．05），得到19个特定的miRNAs。随后，选取4个miRNAs使用实时定量RT—PCR验证HPC和MCAO小鼠脑组织内的miRNAs差异表达。结论19个miRNAs在HPC和MCAO致局部脑缺血小鼠脑内表达发生明显变化，提示其可能在HPC诱导的脑神经保护过程中发挥重要作用。

英文摘要：

Objective To investigate the effects of hypoxic preconditioning （HPC） and middle cerebral artery occlusion （MCAO） on microRNAs expression in the brain of mice. Methods miRNA microarray was used to detect the changes of miRNA expression in the cerebral cortex of HPC mice and the peri-infarct region of MCAO mice. Results Among 656 probes, the expression of 17 miRNAs changed significantly in the cerebral cortex of HPC mice compared with those of control group （ P 〈 0.05, n = 12）. Sixty-five miRNAs changed dramatically in the peri-infarct region of MCAO mice （n = 12） compared with those of the sham control group （P 〈0.05,n = 12）. The expression pattern of 33 miRNAs changed in the peri-infarct region of the HPC and MCAO group （n = 12 ） compared with the peri-infarct region of the MCAO mice （P 〈0.05,n = 12）. Based on Diff Score = ＋ 13 （P = 0.05 ）, 19 differentially expressed miRNAs both changed in HPC and MCAO mice. Then,four miRNAs from the 19 specified miRNAs were randomly chosen as the candidates for verification in HPC and MCAO mice by using qRT-PCR. Conclusions The expression of 19 miRNAs significantly changed in the brain of HPC and MCAO induced-focal cerebral ischemia mice which might involve in cerebral ischemic/hypoxic injuries and HPC-induced neuroprotection.